Question

Will medal and fan!
Mr. and Mrs. Miller both get in their cars and begin to drive at the same time. Mr. Miller is 280 mi from their house and drives directly home at a constant rate of 40 mph. Mrs. Miller is at their house and drives away from the house at a constant rate of 30 mph.
Let d represent distance from home, and let t represent time in hours.
Which system models this situation?
A. d = 280 + 40t
d = 30t

B. d = 280 − 30t
d = 40t

C. d = 280 − 40t
d = 30t

D. d = 280 − 40t
d = 280 + 30t

Answer 1

First off which answers are automatically wrong because of the second equation

Answer 2

Would it be D that's wrong? Sorry, I'm really not great with equations like this. haha!

Answer 3

It's all logical, don't assume you aren't good at it because everyone is capable. Why is the last one wrong?

Answer 4

Because it's irrelevant to Mrs. Miller's equation. Mr. Miller is the one 280 away and he's driving at 40 mph.

Answer 5

Not 30 mph. Am I on the right track? haha...

Answer 6

Yes since D represents distance from house and t represents time elapsed, Mrs. Miller can't have that bottom equation. She starts at the house which is d=0 at t=0. The other three choices can potentially do that for us. So which equation accurately shows her speed and gets Mr. Miller's speed towards the house right?

Answer 7

Yay I was right! :D I personally feel like C. is correct.

Answer 8

Why is C correct?

Answer 9

Because the top equation for Mr. Miller is representing him driving 40 mph subtracted by his distance. The bottom equation represents Mrs. Miller progress, however, the problem only tells us she drives away from home at 30 mph, not how many miles she's driving.

Answer 10

It has nothing to do with how far they are trying to drive. Mr is reducing distance by 40mph and starts at 28p while Mrs starts at 0 and increases distance by 30mph. So yes you're right

Answer 11

280*

Answer 12

Oh, I see! Okay, well thank you so much for your help, I really appreciate it. :)

Answer 13

Yep no problem